Crystal and molecular structures of tricarbonyltechnetium acetylacetonate and its adduct with diethylamine

The crystal and molecular structures of tricarbonyltechnetium acetylacetonate and its adduct with diethylamine were studied by single crystal X-ray diffraction. Tricarbonyltechnetium acetylacetonate crystallizes in the triclinic system, space group \(P\bar 1\), a = 8.1154(1), b = 8.1961(2), c = 8.2695(1) Å, α = 64.5618(9)°, β = 69.7899(8)°, γ = 83.6925(9)°, V = 465.652(14) ų (at 100 K); Z = 2. The adduct also crystallizes in the triclinic system, space group P{ie145-2}, a = 7.9338(3), b = 8.5421(3), c = 12.1506(7) Å, α = 96.961(3)°, β = 99.952(3)°, γ = 112.001(2)°, V = 736.25(6) ų (at 100 K); Z = 2. Tricarbonyltechnetium acetylacetonate has a centrosymmetrical dimeric structure. The dimerization occurs through the formation of a bridging bond with the methine carbon atom of the acetylacetonate ligand which is thus coordinated in the tridentate chelating-bridging fashion. The adduct has a monomeric structure with chelating coordination of the acetylacetonate ligand and coordination of diethylamine to the technetium atom via N atom. In both complexes, the carbonyl groups are in the fac position. Differences between the structures of tricarbonyltechnetium acetylacetonate in the crystal and in solution are discussed.